There seems to be a bug in the i.MX27 used on .0 and .1 module
revisions which breaks SPCTL0 setup. There, SPCTL0 is reset to
0 after reading it causing e.g. a bad USB clock. Hence, this
patch writes back the read value.
Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>